Bladder calculi occur either from migrated renal calculi or urinary stasis. Bladder calculi can be divided into primary and secondary stones:
- primary: stones form de novo in the bladder
- secondary: stones are either from renal calculi which have migrated down into the bladder, or from concretions on foreign material (e.g. urinary catheters)
Primary bladder calculi, in otherwise normal bladders, were previously common, but are now very uncommon in western nations 2. When encountered, the most common cause is due to urinary stasis, including from:
Family history is found in up to one third of idiopathic cases 2.
Bladder calculi may present with pain, infection, haematuria or may be asymptomatic.
Usually densely radiopaque, calculi may be single or multiple and are often large. Frequently lamination is observed internally, like the skin of an onion.
Sonographically they are mobile, echogenic, and shadow distally. They may be associated with bladder wall thickening due to inflammation.
Treatment and prognosis
The earliest method of operative removal of bladder calculus was performed via the perineum with the patient in a supine position and the legs elevated - hence the term lithotomy position.